As integrated circuits become larger and more complex, it is important to improve the control methodology and structure that is used to control various portions of the integrated circuit (IC). Also, one of the methods employed to reduce IC design time is to combine re-usable modules into a single integrated circuit. Re-usable modules can vary from small specialized functional blocks such as an integer multiplier to modules that were formerly an entire IC such as a microprocessor. In addition, re-usable modules can exist in many forms ranging from a synthesizable model which can be readily modified to a physical model which cannot be modified. When un-modifiable re-usable modules are combined in an integrated circuit, problems can arise when attempting to combine them such that new functionality is available at the IC level while retaining the capability to utilize, test, and control all of the functionality of individual re-usable modules. It is thus becoming increasingly important to be able to integrate the control and testing of various re-useable IC portions or modules that were originally designed to be used in different ICs.
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